Toilets that are provided in vehicles, or used for camping purposes or are otherwise portable, are typically made primarily of plastic. Constructing such toilet units of plastic not only is relatively inexpensive and allows simple construction thereof, but also the use of plastic saves weight, which is important in any type of vehicle, or for portability in general. Therefore conventional portable and mobile toilet units include a plastic toilet bowl, a plastic body positioned exteriorly of the toilet bowl, and a plastic toilet seat.
The toilet environment is extremely harsh and plastic components--plastic toilet bowls in particular--have a tendency to degrade more quickly than desired as a result of attack by chemicals and light. While it is thus highly desirable to provide toilet bowls having improved characteristics, so as to extend the life thereof, that desirable goal cannot be achieved by compromising the cost and low weight criteria that are very important for portable and mobile toilets. For example it is not possible--in a manner consistent with low weight and low cost--to replace the plastic toilet bowl with a toilet bowl material, like porcelain, that has outstanding resistance to degradation but relatively high cost and weight.
According to the present invention, a portable or mobile toilet unit is provided which is able to achieve a significantly longer life for the toilet bowl, and increase the hygiene associated therewith, while at the same time only minimally increasing the weight and cost of the toilet unit. This is accomplished according to the present invention by providing a non-polymeric, substantially poreless, material that is substantially not degraded as a result of contact with excrement, light, and toilet bowl cleaning agents, disposed interiorly of the plastic toilet bowl and for contacting liquid and materials passing through the toilet bowl open top. The material has an outlet adjacent the bottom thereof for leading sewage away from the toilet bowl. In appropriate cases the material may be provided as a layer or coating of, for example, porcelain or glazed ceramic (each about 0.3125 inches thick, for example); glass; or corrosion resistant sheet metal, or sheet metal with a corrosion resistant substantially poreless interior coating, (e.g. each about 0.05 inches thick). In the preferred embodiment, however, the material comprises a thin-walled (that is having the minimum thickness necessary for structural integrity considering the material utilized) insert liner which is disposed within and is at least partially supported by (typically almost completely supported by) the interior of the plastic toilet bowl. Using such an insert liner, the plastic toilet bowl itself can be made thinner than in conventional toilet units since it primarily only provides a supporting function; and since the insert liner is at least partially supported by the plastic toilet bowl, it can be thinner than it otherwise would have to be to have the sufficient structural integrity if it served as the only toilet bowl structure.
The insert liner may be attached by adhesive directly to the toilet bowl interior surface, or may be attached thereto by mounting foam. The toilet unit also preferably comprises a liquid flush mechanism which flushes liquid (such as water, or a deodorant liquid as commonly used in conventional vehicle toilets) into and through the insert liner. The insert liner outlet is typically sealed by a lip seal to other components. The plastic body may include an annular plastic cover adjacent the toilet seat and an upper rim of the insert liner may be received by the annular plastic cover. The annular plastic cover may mount a plurality of nozzles for introducing flushing liquid into the toilet bowl, directed against the insert liner, and the plastic toilet bowl may have a substantially radially extending portion which supports the annular plastic cover.
The plastic body may be rotatably supported by a socket, which in turn is rotatable about a substantially vertical axis and is mounted below the toilet bowl and insert liner. Within the socket may be a funnel-shaped conduit, communicating with a connection which passes through a wall of the socket, to lead sewage away from the toilet bowl outlet, e.g. to a holding tank either integral with the toilet unit or--in the case of most vehicles--distinct from the toilet unit. The toilet unit according to the invention is particularly suitable for use with vacuum flush toilets, such as sold by Sealand Technology, Inc. of Big Prairie, Ohio, such as under the "VACU-FLUSH" trademark. A common foot pedal actuator may be provided for operating a valve to supply flushing liquid to the nozzles, and to substantially simultaneously open a spherical segment valve to allow sewage to pass out of the insert liner through the outlet.
It is the primary object of the present invention to provide a toilet unit having necessary lightweight and low cost characteristics, but having enhanced hygiene and longevity of the toilet bowl thereof. This and other objects of the invention will become clear from an inspection of the detailed description of the invention and from the appended claims.